Grippers having the usual fingers which are opened and closed in a generally V-shape relation by means of a power operated actuator are illustrated in U.S. Pat. Nos. 4,167,134, 4,211,123, 4,234,223, 4,492,400 and 4,566,727. Parallel grippers have also been provided utilizing a variety of means for forcefully moving upright parallel gripping members into and out of gripping relation to each other. It is common practice to use a vertically movable cam means for imparting movement to gripping members. Alternatively, linkage means may be utilized rather than a cam for operating the grippers. It is also common practice to utilize longitudinal rails integrally carried by longitudinal side members for supporting a pair of opposed parallel master jaws. Such constructions are expensive, requiring extensive machining.
While square or rectangular cross-sections may be utilized, it is desirable to utilize parallel horizontally spaced mounting bars or rails of circular configuration, because such are less expensive and provide a simple more reliable structural arrangement. The use of parallel circular rails may itself be costly due to the accuracy of alignment required for positioning the gripper mounting blocks or master jaws. Close tolerances would ordinarily be required in providing bores in the mounting blocks which are adapted to receive the rails. Moreover, the means for applying gripping force to the vertical grippers is such that it has generally been impossible to move the grippers into close relationship to each other.
An object of this invention is to provide means for facilitating forceful movement of the parallel grippers through the use of a vertical cam having slots which converge upwardly for accommodating connectors carried by gripper mounting blocks positioned upon end mounted rails.
An important object of the invention is the provision of lateral slots within gripper mounting blocks for accommodating a pair of parallel horizontally spaced circular bars or rails. The rails are positioned upon end brackets without the need for great accuracy in alignment because at least one lateral slot is carried in each of the master jaws permitting some misalignment of the rails. Likewise, minimal machining and alignment of the openings in the blocks is necessitated. Preferably, a bore is provided for one of the parallel rails while one such slot is provided for the other parallel rail.